Differential drive mechanism

ABSTRACT

Cutter and creaser apparatus that cuts and creases sheets and thereafter strips the cutout portions from the sheet includes a drive mechanism that is capable of either intermittently stopping the sheet for the cutting and creasing operations or varying the speed of the sheet as it is conveyed through the cutter and creaser apparatus. The drive mechanism includes a drive shaft driven at constant velocity by suitable drive means. A speed control shaft is mounted in parallel spaced relation to the main drive shaft and is connected thereto by a pair of meshing gears so that the speed control shaft rotates at the same angular velocity as the drive shaft. A sun gear of a planetary gear assembly is connected to the drive shaft for rotation therewith and meshes with a planet gear that, in turn, meshes with the internal toothed portion of the ring gear. The external toothed portion of the ring gear meshes with a drive gear for the press sheet conveyor shaft on which a pair of drive sprockets are mounted in spaced relation to each other. A lever is pivotally connected to the drive shaft intermediate its end portions and has one end portion connected to the planet gear. The other end portion has a cam follower mounted thereon that is maintained in abutting relation with the cam surface of a cam secured to and rotatable with the speed control shaft. The cam upon rotation pivots the lever and moves the planet gear. The angular velocity of displacement of the planet gear through the lever determines the relative velocity of the sheet conveyor. Another embodiment includes bevel gear arrangements to selectively decrease and increase the speed of the conveyor mechanism.

United States Patent [191 Lenoir et al.

[ DIFFERENTIAL DRIVE MECHANISM [75] Inventors: Franz N. Lenoir; Jean Van .Gyseghem, both of Marcinelle,

Belgium [73] Assignee: Miller Printing Machinery Co.,

Pittsburgh, Pa.

[22] Filed: Jan. 14, 1972 [21] Appl. No.: 217,867

Primary Examiner-Arthur T. McKeon AttorneyStanley J. Price, Jr.

[5 7] ABSTRACT Cutter and creaser apparatus that cuts and creases sheets and thereafter strips the cutout portions from the sheet includes a drive mechanism that is capable of either intermittently stopping the sheet for the cutting and creasing operations or varying the speed of the sheet as it is conveyed through the cutter and creaser apparatus. The drive mechanism includes a drive shaft driven at constant velocity by suitable drive means. A speed control shaft is mounted in parallel spaced relation to the main drive shaft and is connected thereto by a pair of meshing gears so that the speed control shaft rotates at the same angular velocity as the drive shaft. A sun gear of a planetary gear assembly is connected to the drive shaft for rotation therewith and meshes with a planet gear that, in turn, meshes with the internal toothed portion of the ring gear. The. external toothed portion of the ring gear meshes with a drive gear for the press sheet conveyor shaft on which a pair of drive sprockets are mounted in spaced relation to each other. A lever is pivotally connected to the drive shaft intermediate its end portions and has one end portion connected to the planet gear. The other end portion has a cam follower mounted thereon that is maintained in abutting relation with the cam surface of a cam secured to and rotatable with the speed control shaft. The cam upon rotation pivots the lever and moves the planet gear. The angular velocity of displacement of the planet gear through the lever determines the relative velocity of the sheet conveyor. Another embodiment includes bevel gear arrangements to selectively decrease and increase the speed of the conveyor mechanism.

4 Claims, 4 Drawing Figures PATENTED BET 91975 SHEEV NF 2 1 DIFFERENTIAL DRIVE MECHANISM CROSS-REFERENCE TO RELATED APPLICATION BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to a differential drive mechanism for conveying sheets in a cutter and creaser apparatus and more particularly to a differential drive mechanism for conveying sheets in a cutter and creaser apparatus that can change the speed of the sheets being conveyed.

2. Description of the Prior Art Differential drive mechanisms are known as disclosed in US. Pat. Nos. 1,162,037, 1,858,763, 1,975,126, 2,159,739, 2,210,734, 2,618,984, 3,076,351 and 3,190,147. There is also known an oscillating drive manufactured and sold by Ferguson Machine Company that includes a barrel type cam with a cam follower that is movable longitudinally relative to the cam surface. The rib of the cam determines the type of reciprocating or oscillating characteristic and timing imparted to the drive shaft. There is a need for a relatively simple drive mechanism in which the type of motion imparted by the drive mechanism may be determined by a conventional cam having a planar cam surface.

SUMMARY OF THE INVENTION The present invention is directed to a drive mechanism for conveying sheets in a cutter and creaser apparatus and includes a first shaft arranged to be rotated at a constant velocity. A second shaft is mounted in parallel spaced relation to the first shaft and in one embodiment is drivingly connected to the drive shaft for rotation therewith and in timed relation thereto. A sheet conveyor drive shaft is mounted in spaced parallel relation to-the first shaft with drive means drivingly connecting the sheet conveyor drive shaft to the first shaft. A speed control means is mounted on one of the first or second shafts and is connected to the drive means between the first shaft and the sheet conveyor drive shaft. The speed control means is arranged to vary the angular velocity of the drive means and thereby vary the angular velocity of the sheet conveyor drive shaft.

In one embodiment the drive means connecting the first shaft which is an input drive shaft and the conveyor drive shaft includes planetary gearing with a sun gear mounted on the input drive shaft and rotatable therewith. A ring gear is positioned coaxially with the sun gear and is drivingly connected to the conveyor drive shaft. A planetary gear meshes with the sun gear and ring gear. The speed control means includes a lever pivotally mounted intermediate its end portions on the input drive shaft and has one end portion connected to the planetary gear. The other end portion has a cam follower thereon which abuts a surface of a rotatable cam mounted on the second shaft which is a speed control shaft. The speed control shaft is drivingly connected to the input drive shaft.

In another embodiment the drive means includes a first compound gear rotatably mounted on a shaft. The first compound gear meshes with a gear on a shaft that is both an input drive shaft and a speed control shaft. The first compound gear has a bevel gear that meshes with a bevel pinion rotatably mounted on a speed control lever. The conveyor drive shaft is drivingly connected to the input shaft through a second compound gear having a bevel gear in meshing relation with the bevel pinion. Rotation of the input drive shaft is transmitted through the first compound gear, bevel pinion and second compound gear to the conveyor drive shaft. A lever having the bevel pinion rotatably mounted at one end is pivotally mounted on the second shaft and has a cam follower mounted thereon.

With the above arrangement the speed control shaft transmits rotation to the cam member which, in turn, through the cam follower, pivots the lever and changes the angular velocity of the drive means between the input drive shaft and the sheet conveyor drive shaft. In one embodiment the lever revolves the planet gear about the sun gear at a predetermined angular velocity to change the angular velocity of the ring gear. In the other embodiment the lever revolves the bevel pinion about a shaft to change the angular velocity between the first and second compound gears.

Accordingly, the principal object of this invention is to provide a drive mechanism where a planar cam configuration controls the angular velocity of the drive mechanism.

Another object of this invention is to provide a differential drive mechanism that includes constantly meshing gearing.

These and other objects and advantages of this invention will be more completely disclosed and described in the following specification, the accompanying drawings and the appended claims.

DESCRIPTION OF THE DRAWINGS FIG. 1 is a view in side elevation and partially in section of a cutter and creaser mechanism in which sheets of cardboard and the like are subjected first to a cutting and creasing operation, thereafter subjected to a stripping operation and then conveyed to a sheet stacking device.

FIG. 2 is a diagrammatic view in section taken along the Line 11-11 of FIG. 1, illustrating schematically the feeding, cutting and creasing, stripping and stacking sections of the apparatus.

FIG. 3 is a perspective view of one embodiment of the drive mechanism suitable for driving the endless chain conveyor.

FIG. 4 is a similar perspective view of another embodiment of the differential drive mechanism for the endless chain conveyor.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to the drawings and particularly FIGS. 1 and 2 there is illustrated a cutter and creaser apparatus generally designated by the numeral 10 that has a sheet feeder unit generally designated by the numeral 12 connected to a press unit generally designated by the numeral 14. The sheets are fed from the feeder unit 12 down the feedboard 16 into the press unit 14 in a conventional manner. The press unit 14 may, for convenience, be segmented into a transfer section 18, a cutter and creaser section 20, a stripping section 22 and a stacker or delivery unit 24. The sheets are supplied to the press 14 along the feedboard l6 and are moved into side and front register on the feedboard l6 and engaged by gripper mechanisms in the transfer section 18. The sheet is accelerated to press speed by apparatus in the transfer section and fed to the press 14.

The press 14 has sheet conveyor apparatus that includes a pair of endless chains 26 mounted on pairs of sprockets 28 adjacent the transfer section 18 and pairs of drive sprockets 30 adjacent the delivery section 24. The endless conveyor chains have a plurality of transverse conveyor bars 32 secured thereto with a plurality of separate grippers 34 thereon. The grippers 34 engage the front edge of the sheet in the transfer section and convey the sheets through the press 14.

Positioned within the cutter and creaser section 20 are pairs of platens 36 and 38 that are arranged to periodically move into abutting relation with each other while a sheet is positioned therebetween to cut and crease the sheet. The platens 36 and 38 and the sheet therebetween are moving toward the stripper section 22 while the sheet is being cut and creased. It is essential that the speed of the conveyor apparatus be substantially the same as the forward speed of the platens 36 and 38. A drive motor 40 is connected by shafting to drive gears for the platens, as is more completely described in co-pending United States application Ser. No. 83,335, and does not form a part of the present invention other than provide rotation for the input drive shaft as later described.

Within the stripper section there are other stripper platens 42 and 44 that are arranged to periodically move into abutting relation with each other and strip or remove the cut out portions from the sheet as the sheet is conveyed through the stripper section 22 to the delivery section 24. A shaft 46 drives the eccentric shaft of the stripper platens to move the platens 42 and 44 in timed relation with the cutter and creaser platens 36 and 38. It is also essential that the sheet conveyor apparatus deliver the cut and creased sheet to the stripper section to be in register with the stripper platens 42 and 44 and also to be at substantially the same speed as the stripper platens 42 and 44 as they move toward the delivery unit 24. The stripper platens 42 and 44 are driven in timed relation to the cutter and creaser platens 36 and 38 by gearing and shaft 46.

The grippers 34 on the transverse gripper bars 32 release the sheet in the delivery section 24 and the cut and creased sheets are stacked on a suitable receiver. A shaft 48 is connected through suitable gearing to the shaft 46 and has a bevel gear 50 suitably connected to an end portion thereof. The bevel gear 50 meshes with bevel gear 52 that is arranged to rotate the differential drive mechanism input drive shaft 54 illustrated in FIG. 3. The differential drive mechanism for the endless conveyor chains 26 of the sheet conveyor apparatus is illustrated in detail in FIG. 3.

In the cutter and creaser the sheet decreases in velocity when it reaches a position between the platens 36 and 38 in the cutter and creaser section 20 of press 14, so that the velocity of the sheet matches the forward velocity of the platens. After the platens 36 and 38 have cut and creased the sheet the sheet velocity again increases to convey the sheet to the stripper section 22.

Within the stripper section 22 the velocity of the sheet again decreases to match the velocity of the platens 42 and 44 in the stripper section 22. The platen 44 moves upwardly and strips the cut out sections from the sheet and after the platen 44 moves away from the sheet the sheet velocity is again increased to convey the sheet to the delivery unit 24. It will be apparent with the cutter and creaser apparatus illustrated in FIGS. 1 and 2 the sheet is conveyed through the press unit 14 at different velocities. It should be understood with the hereinafter described mechanism it is possible to also reduce the velocity of the sheet as it is conveyed through the press unit 14 to stop the forward motion of the sheet for a relatively short preselected period of time. The drive mechanism could thus be utilized with a cutter and creaser mechanism that requires the sheet to intermittantly stop during the cutting and creasing and stripping operations.

Referring to FIG. 3 of the drawings, the differential drive mechanism is generally designated by the numeral 56 and includes the input drive shaft 54 that is connected to the gear 52 illustrated in FIG. 1. The shaft 54 is arranged to rotate at a fixed, constant velocity and has a spur gear 58 mounted thereon for rotation therewith. A speed control shaft 60 is mounted in parallel spaced relation to the drive shaft 54 and has a spur gear 62 secured thereto for rotation therewith. The spur gear 62 meshes with spur gear 58 on drive shaft 54 and the gears 58 and 62 are preferably the same size so that the speed control shaft 60 rotates at the same speed as the drive shaft 54. A cam 64 is secured to the end of the speed control shaft 60 for rotation therewith and has a peripheral cam surface 66 of a preselected configuration.

A sun gear 68 is secured to the end of the drive shaft 54 and meshes with a planet gear 70. The planet gear 70, in turn, meshes with the internal teeth 72 of ring gear 74. With this arrangement, rotation of drive shaft 54 is transmitted through sun gear 68 and planet gear 70 to the ring gear 72 to rotate the ring gear in a direction opposite to the direction of rotation of drive shaft 54.

The sheet conveyor drive sprockets 30 are mounted on a conveyor drive shaft 76 for rotation therewith and have endless chains 26 extending therearound and meshing therewith. The transverse bars 32 with the grippers 34 thereon are suitably connected to the chains 26 and are arranged to convey the sheets through the press unit 14. The shaft 76 has a spur gear 78 connected thereto that meshes with the external toothed portion 80 of ring gear 72. With this arrangement, rotation of the ring gear 72 is transmitted through gear 78 to the endless conveyor drive shaft 76.

A lever 82 is pivotally mounted intermediate its end portion on the drive shaft 54 and the planet gear 70 has a shaft member 84 pivotally mounted to the end portion of lever 82. A cam follower 86 is rotatably mounted on the other end portion of lever 82 and is maintained in abutting relation with the cam surface 66 by a spring 88.

To transmit a constant velocity from drive shaft 54 to the conveyor drive shaft 76 and the endless chain conveyor driven thereby, the cam member 64 would have a configuration to maintain the lever relatively stationary. To provide a differential velocity for the conveyor, the cam 64 has a configuration that pivots the lever about its intermediate pivot connection to the drive shaft 54. When the lever 82 through the cam 64 and cam follower 86 pivots in a clockwise direction as viewed in FIG. 3 and in the same direction as the rotation of the ring gear 74 the velocity of the ring gear 74 is increased by the angular velocity of the lever 82 and the velocity of the sheet conveyor apparatus is increased proportionately. Similarly, to reduce the speed of the conveyor, the cam 64 is arranged to pivot the lever 82 in a counter-clockwise direction as viewed in F IG. 3 and the velocity of the ring gear 74 is decreased by an amount equal to the angular velocity of the lever 82 as it displaces the gear 70 about the inner toothed portion of ring gear 74. The velocity of the sheet conveyor apparatus is proportionally decreased. It will be appreciated that the change in velocity of the conveyor drive shaft is intermittent and the time required to increase and decrease the velocity of the conveyor may either be substantially the same to increase or to decrease the velocity or the time may be substantially different. The configuration of the cam surface 66 controls the velocity and the acceleration and deceleration of the sheet conveyor apparatus.

Referring to FIG. 4 there is illustrated another embodiment of the drive mechanism in which the internal and external toothed ring gear of the embodiment illustrated in FIG. 3 is eliminated and bevel gears meshing with a tapered pinion is substituted therefor. In FIG. 4 the drive mechanism is generally designated by the numeral 100 and includes an input drive shaft 102 with a spur gear 104 mounted thereon. The spur gear 104 meshes with a spur geared portion 106 of a compound gear 108. The compound gear has an outwardly extending bevel gear 110. The compound gear 108 is rotatably mounted on a shaft 112 with spur gear 106 meshing with spur gear 104 to thereby transmit rotation from the input shaft 102 to the bevel gear portion 110 and compound gear 108. The shaft rotatably supports a second compound gear 114 that has a spur gear portion 116 and a bevel gear portion 118. A lever member 120 is pivotally supported intermediate its end portions on the auxiliary shaft 112 and has a bevel geared portion 122 rotatably positioned on an end portion of lever 120. A cam follower 124 is rotatably secured to the other end portion of lever 120 and abuts a cam surface 126 of cam 128. Spring 130 maintains the cam follower 124 in abutting relation with the cam surface 126. The cam member 128 is nonrotatably secured to the input shaft 102 and thus rotates at the same velocity as the input shaft 102. The bevel pinion 122 meshes with the bevel pinions 110 and 118 of compound gears 108 and 114 to transmit rotation of compound gear 108 to compound gear 114 in the opposite direction as indicated by the arrows in FIG. 4. The spur gear portion 116 of compound gear 114 meshes with a spur gear 132 nonrotatably secured to the conveyor drive shaft 134 to increase or decrease the angular velocity of the conveyor drive shaft 134. The lever 120 is pivoted either in the direction of rotation of compound gear 114 or in the direction opposite to the direction of rotation of compound gear 114 by the surface 126 of cam 128. When the lever is pivoted in the direction of rotation of compound gear 114 the velocity of the shaft 134 is increased incrementally by the angular velocity of the lever 120 about the shaft 112. Similarly, when the lever 120 is pivoted in a direction opposite to the direction of rotation of compound gear 114 the velocity of shaft 134 decreases incrementally by the angular velocity of lever as it is displaced around the shaft 112. It will be apparent that the cam surface 126 of earn 128 may have a configuration to match the angular velocity of the lever 120 with the angular velocity of the compound gear 114 to thus counter the rotation of compound gear 108 and stop the shaft 134 for a preselected short period of time. Similarly, the configura tion of the cam surface 126 may be such that the endless chain conveyor for the sheets is increased and decreased at a predetermined rate of acceleration.

It should be understood that the drive mechanism illustrated in either FIGS. 3 or 4 may be positioned on either side of the press unit 14 and a separate drive other than the drive connection through shaft 48 and bevel gears 50 and 52 may be employed without deviating from the hereinabove described invention.

According to the provisions of the patent statutes, we have explained the principle, preferred construction and mode of operation of our invention and have illustrated and described what we now consider to represent its best embodiments. However, we desire to have it understood that, within the scope of the appended claims, the invention may be practiced otherwise than as specifically illustrated and described.

We claim:

1. A drive mechanism for conveying sheets in a cutter and creaser apparatus comprising,

an input drive shaft arranged to be rotated at a constant velocity,

a speed control shaft mounted in parallel spaced relation to said input drive shaft,

a sheet conveyor drive shaft mounted in parallel spaced relation to said input drive shaft,

drive means connecting said input drive shaft to said sheet conveyor shaft,

means drivingly connecting said speed control shaft to said input drive shaft for rotation therewith and in timed relation thereto,

said drive means including a sun gear mounted on said drive shaft for rotation therewith,

a ring gear positioned coaxially with said sun gear,

means drivingly connecting said ring gear to said conveyor drive shaft, a planet gear drivingly connecting said sun gear to said ring gear, and 1 speed control means mounted on said speed control shaft and connected to said drive means between said input drive shaft and said sheet conveyor drive shaft, said speed control means arranged to vary the angular velocity of said drive means and thereby vary the angular velocity of said sheet conveyor drive shaft.

2. A drive mechanism for conveying sheets in a cutter and therewith, apparatus as set forth in claim 1 in which said speed control means includes,

a cam member mounted on said speed control shaft for rotation therwith,

a cam follower urged into abutting relation with a cam surface of said cam member, and

a lever member having said cam follower mounted on one end and the other end connected to said drive means, said lever member arranged to vary the angular velocity of said drive means upon rotation of said lever by said cam member.

3. A drive mechanism for conveying sheets in a cutter and creaser apparatus as set forth in claim 1 in which,

said speed control means includes means to increase and decrease the angular velocity of said ring gear. said planet gear about said sun gear at a prese- 4. A drive mechanism for conveying sheets in a cutter lected angular velocity and through a preselected and creaser apparatus as set forth in claim 1 in which, arc.

said speed control means includes means to revolve 

1. A drive mechanism for conveying sheets in a cutter and creaser apparatus comprising, an input drive shaft arranged to be rotated at a constant velocity, a speed control shaft mounted in parallel spaced relation to said input drive shaft, a sheet conveyor drive shaft mounted in parallel spaced relation to said input drive shaft, drive means connecting said input drive shaft to said sheet conveyor shaft, means drivingly connecting said speed control shaft to said input drive shaft for rotation therewith and in timed relation thereto, said drive means including a sun gear mounted on said drive shaft for rotation therewith, a ring gear positioned coaxially with said sun gear, means drivingly connecting said ring gear to said conveyor drive shaft, a planet gear drivingly connecting said sun gear to said ring gear, and speed control means mounted on said speed control shaft and connected to said drive means between said input drive shaft and said sheet conveyor drive shaft, said speed control means arranged to vary the angular velocity of said drive means and thereby vary the angular velocity of said sheet conveyor drive shaft.
 2. A drive mechanism for conveying sheets in a cutter and creaser apparatus as set forth in claim 1 in which said speed control means includes, a cam member mounted on said speed control shaft for rotation therewith, a cam follower urged into abutting relation with a cam surface of said cam member, and a lever member having said cam follower mounted on one end and the other end connected to said drive means, said lever member arranged to vary the angular velocity of said drive means upon rotation of said lever by said cam member.
 3. A drive mechanism for conveying sheets in a cutter and creaser apparatus as set forth in claim 1 in which, said speed control means includes means to increase and decrease the angular velocity of said ring gear.
 4. A drive mechanism for conveying sheets in a cutter and creaser apparatus as set forth in claim 1 in which, said speed control means includes means to revolve said planet gear about said sun gear at a preselected angular velocity and through a preselected arc. 